80100 direct cooling


it’s exactly the 400A Boat ESC 16S LiPo 68V Opto Flier.
130kv might be a bit fast, no? let us know how it goes, my backup motor after this one burn is a 130kv too :slight_smile:


the hardest is to not forget to hit record… and keep the camera charged…
after that, make enough space on you computer to deal with 400+Go of video and cut it in small pieces… easier than it looks :slight_smile:


Ill post how it goes here for sure. Parts get here this week, and ill be finished by the weekend.

130KV should work, since 190KV worked with smaller diameter motors on my double motor direct drive.

this is the prop Im going to use that I designed in fusion, with a end spacer for the motor that locks the prop on. hopefully it has good top speed, and has decent efficiency with the thin blades.



end cap:


What a great video! You work a lot more organised than I do;)


Awesome job, congratulation Mat


that’s just an impression because the videos are zoomed in :wink:


Did you add capacitors to your flier ESC? I’m trying to work out wether I need to, battery leads are roughly 70cm long so 1.4M all up…

edit: 80cm all up…my bad


ESC is not modified at all… my battery wires are roughly the same length is not a bit more, but as the esc is made for 400A, it should handle the 100+ i guess i’m using without any issues…


One question! How much would you need to charge to make more of them?

I design and make computerized gasoline detectors and that was WAY over my head!

I have be4en a huge proponent of dirct drive with water cooling because that is how deep well pumps are cooled in our industry (Grundfos) so it is really wonderfull to see it so well excetued.


Awesome video Mat !
Do you have datas from your trials regarding Power required for take off and cruising ?


not yet… i’m still trying to find the time to install a elogger inside … hopping to get some data before it burns :slight_smile:


At least it’s the most simple design possible… still not sure of the impact of the extra drag though…

most of the cost is in the time in take i guess… first parts for that one were ordered in March…


Mat before I forget I was very impressed with what you did cutting a groove with the drill press. I have a full machine shop here and it has apparently made me stupid and lacking in creativity :stuck_out_tongue:


All of the patents I have are the simplest solution to a problem. That is what usually makes them successful products. One last time Mat really beautiful work. Props! (ya PUN intended…)


i was planning on using a screw + washer at first, that’s what the hole was for… but then i gave a try to the dremel… such a magic tool :slight_smile:


Hi Mat
The software suggested I message you directly

I have another design I feel is patentable but some university engineers already disclosed it publicly so it can never be patented now but they came up with my deisng independantly, usually the best proof it is viable

anyway they do what outboard motors do and put the motor above the water with a 90 degree helical gear right in the foil like Virus does with carbon moulding

Based on the community’s engineernig abilities this is well within everyone’s ability once we all get to gether to do this

use an aluminum 3/8 oD* or carbon graphite hollow drive shaft wihtout the 2 to 1 reduction than runs inside the mast with a vertical drive motor up top…

*i asked my marine mechanic to give me some old 2-5 HP lower end untis to reverse engineer, saves so much time in desing

  • they use identical diameter drive shafts for all sizes from 2 hp right up to 9 hp before they change up the OD of the drive shaft…

please feel free to make any of the bove public domain

as a physicist i never shut up, sorry not sorry

lastly on a more personal note, you honestly did some really beautiful work on the foam, that is like sculputuring but the hot wire stuff wow…its annoying you made it look so dam easy
pete in a rush have to gt bakc to the paying work :stuck_out_tongue:


Amazing work all around on that build! So much time and effort put into that. The talent on this boards is incredible. A project like this takes so much skill, from electronics, carbon fiber, fiberglass, surfboard shaping, hydrodynamics, prop design to waterproofing etc… Then you have to have the skills to actually ride the thing.
Finally got my build working, thanks for your help!
How many hours and how much did it end up costing you for everything?


that’s very hard to estimate…
25 weeks, around 2 hours each day, a bit less during the week, a bit more during the weekend… so very roughly between 300 and 400 hours i guess… without counting the 70+ hours of reading the forum :slight_smile:
cost wise: esc + motor + battery + mast = 1000$ … then add all the smaller things (wires, connectors, arduinos and electronic bits and pieces, pump, coulomb meter and its successors, plastic for the printer, prop, resin, fiberglass, plywood, polycarbonate, paint, hot-wire, beers…) and you easily double that may be triple… small things add up.


Did you end up doing dual motor?


I’d like to know how much I’ve spent on this whole endeavor.:cold_sweat: Probably not a good idea to add it all up.

No, I ended up using a direct drive motor with an ebike controller using the Boma motor. Figured I need to focus on one attempt. I still have parts for the sss motor with Neugart, an 80100 motor with the prop built into the 3d printed cover and tons of the 6364 motors from e-skateboards. Too many options! I’m going to do a write-up when I get some time to take some pictures. Too much fun to finally be up and riding. I’ll waste more garage time over the winter. I still want to do a wakewinch out of an old hub motor with remote control to wakefoil and sled, maybe a bit of snowboarding with it.